fix double [y/N] in container prune
fix double [y/N] in container prune

Signed-off-by: Victor Vieux <ce584ac70734cfa5a848cd28039798932c7ea675@docker.com>

allencloud/cli,cpuguy83/cli,docker/cli,dnephin/cli,riyazdf/cli,ashfall/cli,allencloud/cli,redpanda/cli,e11137/cli,cpuguy83/cli,dnephin/cli,e11137/cli,gdevillele/cli,thaJeztah/cli,redpanda/cli,Zebrilee/cli,riyazdf/cli,ashfall/cli,thaJeztah/cli,docker/cli,Zebrilee/cli